Depth of knowledge (DOK), explained for teachers

Depth of knowledge, usually shortened to DOK, is a way of describing how complex a task is. It is easy to confuse with Bloom's taxonomy, because both involve levels and both get printed on classroom posters. They answer different questions, and keeping them apart makes both more useful.

Where it comes from

Norman Webb, a researcher at the Wisconsin Center for Education Research, developed DOK in the late 1990s. His purpose was practical: to check whether state standards and state tests actually matched in the complexity of thinking they asked for. A standard might demand that students analyze, while the test only asked them to recall, and Webb wanted a way to see that mismatch. The four levels are commonly summarized as:

1. Recall and reproduction. Facts, definitions, a procedure with one clear route.
2. Skills and concepts. Some decision about method; mental processing beyond recall, such as classifying, comparing or interpreting.
3. Strategic thinking. Reasoning, planning, using evidence, with more than one defensible approach.
4. Extended thinking. Investigations or projects stretching over time that synthesize ideas across sources.

The key difference from Bloom's

Bloom's taxonomy sorts objectives by kind of thinking: remember, apply, evaluate. DOK describes the complexity of the task the student is actually given. A verb does not settle it. Webb's own point was that the same verb can land at different levels depending on content: "describe" a person's physical appearance is recall, while "describe" how two economic systems would respond to a drought is much more demanding. Karin Hess later combined the two frameworks in a grid often called the cognitive rigor matrix, which is the usual way teachers use them together.

A classroom example with fractions

• Level 1: Compute 3/4 + 1/8.
• Level 2: A recipe needs 3/4 cup of flour and 1/8 cup of sugar. A student has a 1-cup scoop. Does the flour and sugar fit in one scoop? Choose the operations and explain your steps.
• Level 3: A student claims that 1/3 + 1/4 = 2/7. Decide whether the claim is right and justify your answer in two different ways.
• Level 4: Over a week, plan a class bake sale: scale three recipes, compare costs, and present a plan, making and defending choices along the way.

Notice that the content is the same all the way through. Only what the student has to do changes.

Common mistakes

• Assigning levels by verb. A verb chart for DOK is a trap. Look at the task, not the stem.
• Equating DOK with difficulty. A level 1 task can be hard (recall a long list) and a level 3 task can be easy for a prepared student. Complexity is not the same as how hard it is for these students.
• Thinking higher is better. A good unit has all four levels in appropriate proportion. Level 1 and 2 knowledge is what makes level 3 reasoning possible.
• Counting level 4 in every unit. By definition level 4 takes time. If every lesson is meant to hit it, you are mislabeling.
• Labeling the task, not the student's actual response. If students solve your level 3 task by memorizing a procedure you showed them, it was level 1 for them.

The honest limits

DOK is a framework for alignment and planning, and it is not a measurement. Two trained raters will often disagree on the level of a particular task, and the boundaries between levels 2 and 3 are the usual place for arguments. There is no body of experiments showing that teaching to a higher DOK level raises achievement by itself, and a framework cannot tell you whether the task is a good one. Its main value is in noticing that your quiz sits entirely at level 1 when your standard asks for more.

How this shows up in ClassSense

It mostly does not, and it is better to say so. ClassSense does not label anything with DOK levels. Its skill extraction uses Bloom's levels internally (see Bloom's taxonomy), and the practice questions students answer are multiple choice, so they tend to cover levels 1 through 3 at best. Level 4 work, such as investigations and projects, is something you design and assess yourself.

If you use DOK to audit assessments, a good practice is to generate an assessment in the Create Content tab, then check each question against the four levels before you use it. Our guide to writing good multiple choice questions covers pushing items beyond recall.

Common questions